Here's the theory. Well before the advent of photography, in paintings of paradoxically photorealistic light and detail such as "Girl With a Pearl Earring" and "The Music Lesson," 17th-century Dutch artist Johannes Vermeer may have used a camera obscura and a couple of mirrors.

The theory imagines Vermeer, in effect, copying — directly, meticulously — from life, with the use of optics.

The Dutchman committed such ravishing acts of beauty on the canvas, perhaps his methods shouldn't affect our experience of the finished work. Or perhaps they should. Art is funny that way.

"Tim's Vermeer" is a diverting 80-minute account of one man's mission to explore the Vermeer optics theory in detail. The Tim in question, video software pioneer Tim Jenison, went about his mission by painting his own damn Vermeer, precisely the way he thinks Vermeer did, with the simple optics the artist may well have deployed in Delft, Holland.

In San Antonio, Jenison re-created Vermeer's "Music Lesson" mise-en-scene, constructing the painting in three dimensions, like a stage set. He then went about re-creating the painting on canvas, stroke for stroke, though Jenison had no formal art training.

The movie elicits the on-screen commentary of art historian Philip Steadman, whose 2001 book "Vermeer's Camera" caused no little controversy. David Hockney, another Englishman, is visited by Jenison and his accompanying crew.

Jenison apparently had money and time enough to pursue his art project. He spent years on the research and then many, many months of continuous work on the completion.

This is a Penn & Teller movie, which makes sense. The veteran illusionists have made their careers on tricks of the eye and how to pull them off. The gabby Penn Jillette hosts and narrates; Teller, the silent one in the act, directs.

Jenison is the amiable if somewhat dull center of the film. Watching the movie is a little like watching "Vertigo" starring a guy who has his obsessions relatively under control.

It's an odd film, ultimately rewarding, because it's about an odd venture. Historian Steadman argues in the film that if Vermeer indeed worked this way, it wasn't cheating. And "the reason it isn't cheating," he says, "is that it's hard."